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Article: The "x-Factor" index: A new parameter for the assessment of adolescent idiopathic scoliosis correction

TitleThe "x-Factor" index: A new parameter for the assessment of adolescent idiopathic scoliosis correction
Authors
KeywordsCorrection
Curve
Flexibility
Fulcrum bending
Index
Radiograph
Rate
Scoliosis
X-Factor
Issue Date2011
PublisherSpringer. The Journal's web site is located at http://www.springer.com/medicine/orthopedics/journal/586
Citation
European Spine Journal, 2011, v. 20 n. 1, p. 144-150 How to Cite?
AbstractThe correction rate (CR) and fulcrum bending correction index (FBCI) based on the fulcrum bending radiograph (FBR) were parameters introduced to measure the curve correcting ability; however, such parameters do not account for contributions by various, potential extraneous "X-Factors" (e.g. surgical technique, type and power of the instrumentation, anesthetic technique, etc.) involved in curve correction. As such, the purpose of the following study was to propose the concept of the "X-Factor Index" (XFI) as a new parameter for the assessment of the correcting ability of adolescent idiopathic scoliosis (AIS). A historical cohort radiographic analysis of the FBR in the setting of hook systems in AIS patients (Luk et al. in Spine 23:2303-2307, 1998) was performed to illustrate the concept of XFI. Thirty-five patients with AIS of the thoracic spine undergoing surgical correction were involved in the analysis. Plain posteroanterior (PA) plain radiographs were utilized and Cobb angles were obtained for each patient. Pre- and postoperative PA angles on standing radiograph and preoperative fulcrum bending angles were obtained for each patient. The fulcrum flexibility, curve CR, and FBCI were determined for all patients. The difference between the preoperative fulcrum bending angle and postoperative PA angle was defined as AngleXF, which accounted for the correction contributed by "X-Factors". The XFI, designed to measure the curve correcting ability, was calculated by dividing Angle XF by the fulcrum flexibility. The XFI was compared with the curve CR and FBCI by re-evaluating the original data in the original paper (Luk et al. in Spine 23:2303-2307, 1998). The mean standing PA and FBR alignments of the main thoracic curve were 58.3° and 24.5°, respectively. The mean fulcrum flexibility was 58.8%. The mean postoperative standing PA alignment was 24.7°. The mean curve CR was 58.0% and the mean FBCI was 101.1%. The mean XFI was noted as 1.03%. The CR was significantly positively correlated to curve flexibility (r = 0.66; p < 0.01).The FBCI (r = -0.47; p = 0.005) and the XFI (r = -0.45; p = 0.007) were significantly negatively correlated to curve flexibility. The CR was not correlated to AngleXF (r = 0.29; p = 0.089).The FBCI (r = 0.97; p < 0.01) and the XFI (r = 0.961; p < 0.01) were significantly positively correlated to AngleXF. Variation in XFI was noted in some cases originally presenting with same FBCI values. The XFI attempts to quantify the curve correcting ability as contributed by "X-Factors" in the treatment of thoracic AIS. This index may be a valued added parameter to accompany the FBCI for comparing curve correction ability among different series of patients, instrumentation, and surgeons. It is recommended that the XFI should be used to document curve correction, compare between different techniques, and used to improve curve correction for the patient. © 2010 Springer-Verlag.
Persistent Identifierhttp://hdl.handle.net/10722/92930
ISSN
2014 Impact Factor: 2.066
2014 SCImago Journal Rankings: 1.259
PubMed Central ID
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorSun, YQen_HK
dc.contributor.authorSamartzis, Den_HK
dc.contributor.authorCheung, KMCen_HK
dc.contributor.authorWong, YWen_HK
dc.contributor.authorLuk, KDKen_HK
dc.date.accessioned2010-09-22T05:04:07Z-
dc.date.available2010-09-22T05:04:07Z-
dc.date.issued2011en_HK
dc.identifier.citationEuropean Spine Journal, 2011, v. 20 n. 1, p. 144-150en_HK
dc.identifier.issn0940-6719en_HK
dc.identifier.urihttp://hdl.handle.net/10722/92930-
dc.description.abstractThe correction rate (CR) and fulcrum bending correction index (FBCI) based on the fulcrum bending radiograph (FBR) were parameters introduced to measure the curve correcting ability; however, such parameters do not account for contributions by various, potential extraneous "X-Factors" (e.g. surgical technique, type and power of the instrumentation, anesthetic technique, etc.) involved in curve correction. As such, the purpose of the following study was to propose the concept of the "X-Factor Index" (XFI) as a new parameter for the assessment of the correcting ability of adolescent idiopathic scoliosis (AIS). A historical cohort radiographic analysis of the FBR in the setting of hook systems in AIS patients (Luk et al. in Spine 23:2303-2307, 1998) was performed to illustrate the concept of XFI. Thirty-five patients with AIS of the thoracic spine undergoing surgical correction were involved in the analysis. Plain posteroanterior (PA) plain radiographs were utilized and Cobb angles were obtained for each patient. Pre- and postoperative PA angles on standing radiograph and preoperative fulcrum bending angles were obtained for each patient. The fulcrum flexibility, curve CR, and FBCI were determined for all patients. The difference between the preoperative fulcrum bending angle and postoperative PA angle was defined as AngleXF, which accounted for the correction contributed by "X-Factors". The XFI, designed to measure the curve correcting ability, was calculated by dividing Angle XF by the fulcrum flexibility. The XFI was compared with the curve CR and FBCI by re-evaluating the original data in the original paper (Luk et al. in Spine 23:2303-2307, 1998). The mean standing PA and FBR alignments of the main thoracic curve were 58.3° and 24.5°, respectively. The mean fulcrum flexibility was 58.8%. The mean postoperative standing PA alignment was 24.7°. The mean curve CR was 58.0% and the mean FBCI was 101.1%. The mean XFI was noted as 1.03%. The CR was significantly positively correlated to curve flexibility (r = 0.66; p < 0.01).The FBCI (r = -0.47; p = 0.005) and the XFI (r = -0.45; p = 0.007) were significantly negatively correlated to curve flexibility. The CR was not correlated to AngleXF (r = 0.29; p = 0.089).The FBCI (r = 0.97; p < 0.01) and the XFI (r = 0.961; p < 0.01) were significantly positively correlated to AngleXF. Variation in XFI was noted in some cases originally presenting with same FBCI values. The XFI attempts to quantify the curve correcting ability as contributed by "X-Factors" in the treatment of thoracic AIS. This index may be a valued added parameter to accompany the FBCI for comparing curve correction ability among different series of patients, instrumentation, and surgeons. It is recommended that the XFI should be used to document curve correction, compare between different techniques, and used to improve curve correction for the patient. © 2010 Springer-Verlag.en_HK
dc.languageengen_HK
dc.publisherSpringer. The Journal's web site is located at http://www.springer.com/medicine/orthopedics/journal/586en_HK
dc.relation.ispartofEuropean Spine Journalen_HK
dc.rightsThe original publication is available at www.springerlink.com-
dc.subjectCorrectionen_HK
dc.subjectCurveen_HK
dc.subjectFlexibilityen_HK
dc.subjectFulcrum bendingen_HK
dc.subjectIndexen_HK
dc.subjectRadiographen_HK
dc.subjectRateen_HK
dc.subjectScoliosisen_HK
dc.subjectX-Factoren_HK
dc.subject.meshBone Screws-
dc.subject.meshRadiographic Image Interpretation, Computer-Assisted-
dc.subject.meshRange of Motion, Articular-
dc.subject.meshScoliosis - radiography - surgery-
dc.subject.meshThoracic Vertebrae - radiography - surgery-
dc.titleThe "x-Factor" index: A new parameter for the assessment of adolescent idiopathic scoliosis correctionen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0940-6719&volume=20&issue=1&spage=144&epage=150&date=2011&atitle=The+%27X-Factor%27+Index:+a+new+parameter+for+the+assessment+of+adolescent+idiopathic+scoliosis+correction-
dc.identifier.emailSamartzis, D:dspine@hku.hken_HK
dc.identifier.emailCheung, KMC:cheungmc@hku.hken_HK
dc.identifier.emailLuk, KDK:hcm21000@hku.hken_HK
dc.identifier.authoritySamartzis, D=rp01430en_HK
dc.identifier.authorityCheung, KMC=rp00387en_HK
dc.identifier.authorityLuk, KDK=rp00333en_HK
dc.description.naturelink_to_OA_fulltext-
dc.identifier.doi10.1007/s00586-010-1534-3en_HK
dc.identifier.pmid20714756en_HK
dc.identifier.pmcidPMC3036025-
dc.identifier.scopuseid_2-s2.0-78651502969en_HK
dc.identifier.hkuros173074-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-78651502969&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume20en_HK
dc.identifier.issue1en_HK
dc.identifier.spage144en_HK
dc.identifier.epage150en_HK
dc.identifier.isiWOS:000285972500020-
dc.publisher.placeGermanyen_HK
dc.identifier.scopusauthoridSun, YQ=12806809700en_HK
dc.identifier.scopusauthoridSamartzis, D=34572771100en_HK
dc.identifier.scopusauthoridCheung, KMC=7402406754en_HK
dc.identifier.scopusauthoridWong, YW=36247941700en_HK
dc.identifier.scopusauthoridLuk, KDK=7201921573en_HK
dc.identifier.citeulike7704596-

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